A long isoform of the epithelial sodium channel alpha subunit forms a highly active channel.

ABSTRACT: A long isoform of the human Epithelial Sodium Channel (ENaC) α subunit has been identified, but little data exist regarding the properties or regulation of channels formed by α728. The baseline whole cell conductance of oocytes expressing trimeric α728βγ channels was 898.1±277.2 and 49.59±13.2 µS in low and high sodium solutions, respectively, and was 11 and 2 fold higher than the conductances of α669βγ in same solutions. α728βγ channels were also 2 to 5 fold less sensitive to activation by the serine proteases subtilisin and trypsin than α669βγ in low and high Na+ conditions. The long isoform exhibited lower levels of full length and cleaved protein at the plasma membrane and a rightward shifted sensitivity to inhibition by increases of [Na+]i. Both channels displayed similar single chann

SUBMITTER: Berman JM 

PROVIDER: S-EPMC4594420 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature